> Firefox is (and has been) no longer a consideration in web development because of its tiny and thus inconsequential market share.
Is 7.4% of desktop users [0] inconsequential? Maybe to your business, but I think most would be sad to lose 7% of desktop users. I'll also note if this indicates "death" Safari is dead too.
I know XUL pissed off a lot of people, but I really don't think copying Chrome was the main motivation. XUL had a LOT of cruft and issues they wanted to escape and going to web extensions for some level of interoperability made sense, and looking at data from around that time [1] it doesn't appear to have cost them much of their user-base. It's also a perfect example of Firefox not copying Chrome, with Firefox supporting a ton of APIs Chrome doesn't or has removed [2].
As for the UI "copying" Chrome, I'm not sure how to respond to that. I just spun up vanilla profiles of Firefox and Chrome, and sure they both have tabs at the top, but they are pretty visually distinct. Yes Firefox has reduced the size of it's UI over the years, but if that's copying Chrome... I guess a lot of apps are.
Firefox may be in decline, and that makes me sad, but I think that has a lot more to do with shitty developers using non-standard Chrome APIs and then telling users to use Chrome when it breaks, while GMail and other Google properties cripple Firefox performance, rather than Firefox blindly copying Chrome.
Personally I hope this trend reverses. Firefox is the only thing stopping Chrome from becoming the next IE 6.
[0] - https://gs.statcounter.com/browser-market-share/desktop/worl...
[1] - https://gs.statcounter.com/browser-market-share/desktop/worl...
[2] - https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...